1. Field of the Invention
The instant disclosure relates to a motor speed curve control circuit; in particular, to a motor speed curve control circuit that can adjust the motor speed curve and a motor using the same.
2. Description of Related Art
With the development of technology, motors have become essential electric devices in society. The common motors, such as DC motors, AC motors, step motors and the like, have been widely used for driving fans.
In order to drive the motor, the motor driving chip comprises a Hall sensor. The Hall sensor outputs the timing signal to the control circuit according to the working state of the motor, such as the current direction and the current amount of the coil of the motor. The control circuit controls the conducting states of each switch in the full-bridge circuit according to the timing signals and the pulse width modulation signals, which makes the permanent magnet of the motor rotator and the coil attract or repel with each other. Thereby, the motor can drive the fans to rotate.
A curve drawn based on the relationship between the duty cycle of the input pulse width modulation signal and the corresponding speed thereof is considered to be the motor speed curve. For example, the vertical axis of the motor speed curve represents for the motor speed, and the horizontal axis of the motor speed curve represents for the duty cycle of the input pulse width modulation signal. The characteristics of the motor can be learned according to the motor speed curve. The motor speed curve of the traditional motor is a non-linear curve, and thus it would not be accurate enough for the control circuit to control the motor.